There are two basic spray bottle or spray can configurations: one employs a hand pump (sometimes referred to as "trigger") device to draw the liquid up the feed tube (sometimes referred to as "dip tube") and then sprays the liquid out of the exit port; the second employs a pressurized gas to force the liquid contents out when the exit value is actuated. The use of hand pump bottles or pressurized cans to dispense a wide variety of substances such as glass cleaner, paint, and perfume, is widespread. Most of these containers have a single dip tube with an open end that extends into the liquid contents when the container is held in an upright position. However, when the container is inverted, the dip tube entrance is exposed to gas, and then only gas can be expelled from the container.
There are numerous patents which relate to the design of novel feed structures and hand pumps that can operate in either the fully upright position or the fully inverted position. The teachings of many of these patents are based on using check valves that are dependent on the force of gravity. One group (e.g. Grothoff U.S. Pat. No. 4,775,079) employs one or two balls that open or close flow passages depending on the orientation of the container utilizing the force of gravity. The other group (e.g. Ramsey U.S. Pat. No. 3,733,013) employs slugs that open or close flow passages and also utilize the force of gravity. When the bottle is partially inverted so that the open end of the dip tube is not in contact with liquid, but the component of the force of gravity is insufficient to move the ball or slug to either seat or unseat the port, the system will expel gas rather than liquid. Because of the difficulty of obtaining an acceptable gas seal with a ball or slug which is held in position by gravity, none of these patents teaches a concept that will reliably operate at orientations between the fully upright and the fully inverted positions.
Another group of patents describes dip tube configurations that will pass some types of fluids but not others. These concepts do not require check valves to control the flow into the dip tube but can operate only in the upright position. One type is for dispensing a three-phase system wherein phase I is a gaseous propellant and phases II and III are two immiscible liquids. In these patents, a dip tube is described that allows one phase of material to pass but prevents the entrance of another phase. In particular, Pong et al (U.S. Pat. No. 4,418,846) describes two immiscible liquids, one of which is a lipophilic phase and the other is a non-lipophilic phase. The dip tube has an open end through which the non-lipophilic phase flows and a tubular structure formed of a lipophilic material having multi-directional pores through which the lipophilic phase flows. The lipophilic liquid is thereby combined with the non-lipophilic liquid and the combination is passed through the valve means and is dispensed through the valve. Pong et al (U.S. Pat. No. 4,398,654) describes a similar dip tube with an open end through which can pass an aqueous liquid and a tubular structure through which a non-aqueous liquid will flow. These structures operate satisfactorily only if the container is in an upright position.
There is yet another patent which is of interest in the teaching of the present patent. This patent (Naess U.S. Pat. No. 4,529,414) describes a design for the separation of gas from a liquid in a flow system having at least one permeable blocking layer so arranged along the length of the pipe that the liquid remains on the underside of the blocking medium. This system relies on surface tension and capillary forces to separate the gas from the liquid. It is of interest only because it employs surface tension forces to separate the gas and liquid since it is not related to spray bottles in any manner.
There are several patents for propellant feed systems that operate in zero or near zero gravity fields. Ellion et al (U.S. Pat. No. 4,272,257) is typical of these patents which rely on surface tension to allow liquid to flow and prevent the discharge of gas. A summary article for these zero-gravity rocket motor feed systems is given in the Journal of Spacecraft and Rockets Vol. 8 No. 2 February 1971 pages 83-88 by S. Debrok. Although these patents employ surface tension devices to prevent gas from leaving the container, none of them relates to spray bottles that operate in a gravity field and they all require multiple, complex, expensive porous entrance devices.
It is a principal object of this invention to provide a feed system for a hand held spray bottle that is usable when the bottle is at any orientation.
It is another object of this invention to provide a feed system that operates automatically without requiring manipulation on the part of the user.
It is yet another object of this invention to be able to operate this container feed system on earth and consequently in a gravity field or at any gravity level above or below earth's gravity level.
It is still another object of this invention to provide the features of this invention at very low cost of production.
It is still another object of this invention to provide a simple, inexpensive feed system that requires little or no added assembly steps over those required for the existing conventional spray bottles, and can be assembled with established production line equipment.
Other objects and advantages of this invention will become apparent from the following specifications and appended drawings.